A Cleveland doctor's work indicates that popping too many over-the-counter painkillers could result in more frequent headaches. Doctor David Rothner says he sees a steady stream of teenagers who complain of almost-daily headache despite popping pain pills up to eight times a week. Many are diagnosed as having rebound headaches, where the more painkiller some people use, the more likely new headaches are to crop up between doses. Headache specialists say it's not uncommon for adults to fall into that trap. And Rothner's check of records at the Cleveland Clinic suggests a surprising number of teens and preteens may, too. Of 680 patients referred to the hospital's pediatric headache center, 22 percent were overusing nonprescription headache medicine - meaning at least three doses a week for more than six weeks.